3) Something for marking where to cut the insulation - chalk, pastel, paint, sharpie - you just have to be able to see the marks

4) An Exacto knife... this will need a fresh blade!

Step 2: Cut insulation

Cut a length of insulation to fit on a side of your container.

Step 3: Mark the area for cuts

Mark on the end of the foam where the brushes will fit without hitting the top rim of the container... You must leave enough room at the bottom (next to the tube opening) so that there is enough material to hold it all together.

Mark along the length of the insulation at those two points. You will not want to cut slits beyond these lines.

Step 4: Mark slits for brushes

Mark out slits for the brushes. Bigger brushes need wider slits, so you'll probably want a variety of widths. The length of the slits will all be the same. Important....The ends of the slits need to be bigger so that the foam doesn't just 'spit out' the brush when you push it in.

Step 5: Cut the slits

Use an exacto knife with a NEW blade to cut your slits.

When done, put the holder on your water container and try it out. You may find that you want to do more trimming.

Step 6: Dry brushes, too!

Bonus! Dry your brushes safely! You can put this brush holder on a weighted cardboard box to safely dry your (completely cleaned) brushes tip downward. Rocks, water bottles etc work well as weights.